“…Remifentanil is a synthetic opioid that is commonly used during anaesthesia owing to its rapid onset, ultra-short duration of action and quick recovery ( Thompson and Rowbotham, 1996 ). Intraoperative use of remifentanil was, however, associated with paradoxically increased pain hypersensitivity, commonly known as opioid-induced hyperalgesia, and significant additional amount of opioid was required for postoperative analgesia, suggesting acute analgesic opioid tolerance ( Komatsu et al, 2007 , Guignard et al, 2000 , Crawford et al, 2006 , Suhitharan et al, 2018 , Wu et al, 2019 , de Hoogd et al, 2018 , Sanfilippo et al, 2016 , Grape et al, 2019 , Fletcher and Martinez, 2014 , Motamed et al, 2017 ). Development of acute opioid-induced receptor tolerance remains a major focus in understanding the underlying mechanism of this observation ( Guignard et al, 2000 , Vinik and Kissin, 1998 ).…”